Understanding my shutter speeds....

Discussion in 'Fuji X100 Forum' started by kevenv, Feb 5, 2012.

  1. kevenv

    kevenv SC Regular

    96
    Apr 28, 2011
    I know that according to the manual, 1/4000 and 1/2000 should not be available at f/2. Just for fun I took these three pics. The first is at 1/1000, then 1/2000 and finally 1/4000. All were at f/2 with ISO set to 200. Without worrying about the exposure of each shot, I wanted to see what the exif data would say for the shots with the supposed unavailable shutter speeds. As you can see all three pics have a different exposure. When you look at the EXIF data it says exposure time is 1/1000 for the first shot (which was set), 1/1000 for the second (Set at 1/2000) and 0/1 for the 3rd (set at 1/4000). Can someone explain what I am seeing?
    Thanks

    1_1024x681.jpg

    2_1024x681.jpg

    3_1024x681.jpg
     
  2. Ray Sachs

    Ray Sachs SC Legend Subscribing Member

    Sep 21, 2010
    Not too far from Philly
    Real Name:
    you should be able to figure it out...
    What mode are you shooting in? In aperture or shutter priority, I don't believe it will allow these combinations. In manual mode, you can over-ride the camera and use them and it will just warn you with red shutter speed and/or aperture numbers in the screen. As for the exif showing 1/1000 for each, I have no idea...

    -Ray
     
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  3. kevenv

    kevenv SC Regular

    96
    Apr 28, 2011
    Thanks Ray, I was in full manual, F2, ISO200. If I can over ride it in this mode does it mean I am shooting at 1/4000? There are certainly differences in the exposures so the shutter speeds must be different.
     
  4. Luke

    Luke Super Moderator Moderator Subscribing Member

    Nov 11, 2011
    Milwaukee, WI USA
    Real Name:
    Luke
    For some reason, you CAN shoot at f2 at 1/4000 in full manual mode even though you can't in A Priority mode. I just read it somewhere else. I don't why you can, I just know you can.
     
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  5. Isoterica

    Isoterica SC Hall of Famer

    Dec 6, 2011
    I think the auto presets are created with IQ in mind. You can override that in Manual because you are doing all the thinking, the camera is not, and you might choose to over or underexpose or desire grain where out of the box the camera is manufactured to fight noise. As to why it doesn't reflect in your exif, that I don't know. If the option is there it would seem that the camera should record it. Could it be something in settings? My only suggestion is to look there.
     
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  6. Ray Sachs

    Ray Sachs SC Legend Subscribing Member

    Sep 21, 2010
    Not too far from Philly
    Real Name:
    you should be able to figure it out...
    I don't think its about auto presets or the camera making decisions - I just don't think the X-100 has the ability to over-ride your manual settings so all it does is warn you. If you're setting the aperture but IT'S setting the shutter speed, it won't set a speed that won't work with the aperture you're using and vice versa. But if you're setting the aperture AND the shutter speed and the controls have a mechanical interface (even if its technically still done electronically), its not going to let you turn the shutter speed dial to 1/4000 but only expose at 1/1000. The reason it has those limitations is because of the leaf shutter, which for reasons I don't fully understand, can't clear the entire larger apertures at the fastest shutter speeds within the allotted time. Hence, you can technically get some blockage of the frame with the shutter that hasn't cleared the whole aperture in, say, 1/4000 of a second. I can't really explain this very well, but the DPR review of the camera had a pretty good explanation and some illustrations of what can happen when you combine too large and aperture with too fast a shutter speed. Its about halfway down this page: Fujifilm FinePix X100 Review: 17. Photographic tests: Digital Photography Review

    Hope this helps. It doesn't fully explain the exif and something about this was changed in firmware 1.1, but I'm not sure what exactly.

    -Ray
     
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  7. kevenv

    kevenv SC Regular

    96
    Apr 28, 2011
    Thanks for all the replies!

    A quick update. I also posted this on another site and the answer there made it very clear.

    "The difference in exposure is from the fact that the shutter did not completely clear the full sensor before shutting back off (since it needs at least 1/1000 to open/close fully) So instead of shorter exposure you are getting a smaller aperture, but with a sort of wedge shape instead of a circle. Take a picture of an out of focus point of light at f/2 1/4000, and you will see how far the shutter was able to clear by the shape of the bokeh ball - it won't be a circle.


    Thanks for your explanation. Just to make sure I understand what you are saying, in full manual, the camera is still shooting at 1/4000 at f/2 but the shutter doesn't move far enough to clear the full aperture in that amount of time?
    "

    The poster actually followed up with some pics showing the phenomenon. It is at:

    http://www.x100forum.com/index.php?...ed-in-exif-data/page__gopid__37581#entry37581

    Entry number 8.

    The poster told me the EXIF data was showing correct on his pics. I then imported my originals into LR and the data is in fact correct. Where it shows up wrong is in "Preview" on my Mac. I guess that is where the problem lies, not with the camera. Good to know for future ref.